Published: September 15, 2026
The Ad Weight: Network metric describes the network resource consumption by ads, which may impact page performance.
How Chrome calculates Ad Weight: Network
Ad Weight: Network is measured throughout the life of the page visit. The total compressed wire bytes transferred to load all ad-related resources—such as scripts, images, and stylesheets—are computed as:
Ad Weight: Network is reported in kilobytes as an integer rounded to the nearest kilobyte.
The Chrome User Experience Report (CrUX) aggregates data across all eligible Chrome users, and provides a 75th percentile number across those page views. Only pages with ads are considered for the CrUX ad metrics. Pages and origins without at least one authorized seller defined in ads.txt file won't have ad metrics data in CrUX. This data is available at the URL and origin-level, subject to the CrUX eligibility criteria.
Collecting Ad Density through JavaScript
There are challenges reporting across cross-origin iframes which most ads are delivered through. Therefore, there is no JavaScript API to allow similar detection for Real User Monitoring (RUM) tooling.
Tooling
Ad Weight: Network is available in the CrUX API, CrUX History API, and the DevTools Ad panel. To learn more about using these tools, see the CrUX ad metrics tooling guide.
We are working on adding the ad metrics to the CrUX dataset on BigQuery to enable users to query and analyze the ad metrics using SQL.
Feedback
If you have any questions or feedback regarding ad metrics, reach out to us at the Chrome UX Report Google Group.